ASTR 001 Lecture Notes - Lecture 12: Kilogram
Document Summary
In the sun, an exact balance between the inward pull of gravity and the outward pressure of energy release is maintained. Also, the sun radiates from its surface exactly as much energy as it produces in its core. Fusion only occurs in the cores of stars. The protons have the same electric charge and repel each other. Only the hottest gases can undergo fusion; and only in the very center of the sun are high enough temperatures reached (15 million k! Lsun = 4 x 10^26 joules/ second (joule is unit of energy) E = mc2 = 4 x 10^26 joules (energy produced each second) M = 4. 4 x 10^9 kg of matter is converted to energy each second! But: for every kilogram of hydrogen burnt, only 7 grams are converted to energy. So, this means burn ~ 6 x 10^11kg of h per second ~ 2 x 1019kg/year.
